98 LICE AND THEIR MENACE TO MAN 



only 20 per cent passed on to or near the secondary 

 host, 9 '5 per cent of these being inside the pyjamas. 

 When the primary host was febrile 44 per cent 



Lice. 



Lice. 



3 J 



352 

 3 OX 



10Z 



153: 



10% 

 5% 



CHART III. ILLUSTRATING THK EFFECT OF FEVER ox THE 

 MIGRATION OF LICE. 



The continuous line represents the migration when both Primary 

 Host (P.H.) and Secondary Host (S.H.) were afebrile. 



The broken line represents the migration when the Primary Host 

 (P.H.) was febrile and the Secondary Host (S.H.) afebrile. 



Each curve represents the movements of 600 lice. 



of the lice only remained on or near him, 15*5 

 per cent being inside his pyjamas, while 38*5 

 per cent passed on to or near the secondary host, 

 12'5 per cent being inside his pyjamas. The 



